It is known to provide open topped railway cars, whether bottom dump hoppers or top unloading gondolas, which may be fitted with removable covers to enclose the top opening. These covers typically may be lifted free of the cars for loading, or, in the case of gondolas, for unloading. Once a load has been loaded or unloaded, the cover may be replaced.
Such covers provide a number of benefits, including product containment, for example, prevention of ingress of dust, which represents an environmental hazard, and prevention of product loss, and product protection, for example, protection from rain or snow, and protection from debris. Many different granular or powder products may be shipped in this way, including minerals, grains, hazardous waste, coal, etc.
Typically, covers are fastened onto railcars by the use of various types of clamps or brackets, which fix the cover to the car and prevent it from coming loose in transit, but which allow manual or automatic opening in order to handle the cover.
Covers typically may be manufactured of steel, aluminum, or various composite materials, each of which has it's advantages and disadvantages. Covers may be built as a single piece covering the full length and width of the railcar, or as two or more pieces, depending on the material selected and the circumstances of operation. Due to their large size, railcar covers require heavy equipment, whether fixed or mobile, for removal and replacement, as well as large areas for moving and stacking removed covers.
The weight of each cover can be significant, ranging from as little as 1500 lbs for a composite cover, to as much as 5000 lbs for a steel cover. The cover weight reduces the effective payload of the railcar, thereby reducing the cargo load the user can haul.
In high volume situations, it is often not possible to arrange a suitable method for removal and replacement of covers. For instance, in a coal loading facility, the railcars typically do not stop moving, but are driven slowly in one long string through the facility, under loading chutes, and exit the far side of the loading facility, which may be several hundred feet away. Slowing or stopping of trains is generally not an option. The logistics of lifting covers off at the entrance to the facility, moving them around the facility to the loadout area at the loading facility exit, and replacing the covers on the railcars, make use of covers very problematic. As a result, to date, no large scale loading operations of this type have been converted to covered cars.
On the unloading end, the problem is similar. For unloading gondola type railcars, high volume operations such as coal will use a railcar dumper, a large device which rotates about the axis of the railcar couplers, completely inverting one or more railcars at a time, while they remain coupled to the cars ahead and behind. Again, covers would have to be removed from cars entering the dumper building, moved around the building, and replaced on the other side.
Past and current solutions have included lifting of covers within the dumper building over the dumper itself. This adds time to the dump cycle, and is not suitable for retrofit situations, as dumper buildings typically do not have the space capacity for such a cover lifting mechanism, and many dumpers are constructed with part of their mechanism over top of the car, which would prevent removal of the railcar cover. This solution also would not work at the loading end. Accordingly, a new cover removal system is needed.